Method and apparatus for measuring and feeding back channel information

Abstract

A method and an apparatus for measuring and feeding back channel information are disclosed. In an embodiment the method includes receiving, by a first network device, a reference signal and measuring the reference signal to obtain a measurement result. The method further includes selecting a first codebook from a first codebook set according to the measurement result, wherein the first codebook set comprises at least two first codebooks, a sub-vector W x of each first codebook is formed by a zero vector and a non-zero vector, wherein the vectors forming the W x correspond to different groups of antenna ports, and sending a codebook index to a second network device, wherein the codebook index corresponds to the first codebook selected from the first codebook set.

What is claimed is: 
     
       1. A method for measuring and feeding back channel information, the method comprising:
 receiving, by a first network device, a reference signal; 
 measuring the reference signal to obtain a measurement result; 
 selecting a first codebook from a first codebook set according to the measurement result, wherein the first codebook set comprises at least two first codebooks, a sub-vector W x  of each first codebook is formed by a zero vector and a non-zero vector, wherein the zero and non-zero vectors forming the sub-vector W x  correspond to different groups of antenna ports, wherein each first codebook comprises at least one first sub-vector 
 
       
         
           
             
               
                 [ 
                 
                   
                     
                       
                         V 
                         a 
                         0 
                       
                     
                   
                   
                     
                       0 
                     
                   
                   
                     
                       
                         V 
                         a 
                         1 
                       
                     
                   
                   
                     
                       0 
                     
                   
                 
                 ] 
               
                 
             
           
         
          or at least one second sub-vector 
       
       
         
           
             
               
                 [ 
                 
                   
                     
                       0 
                     
                   
                   
                     
                       
                         V 
                         b 
                         0 
                       
                     
                   
                   
                     
                       0 
                     
                   
                   
                     
                       
                         V 
                         b 
                         1 
                       
                     
                   
                 
                 ] 
               
               ⁢ 
               
                   
                 , 
               
             
           
         
          and wherein V a   0  and V a   1  are elements in a vector V a , and V b   0  and V b   1  are elements in a vector V b ; and 
         sending a codebook index to a second network device, wherein the codebook index corresponds to the first codebook selected from the first codebook set. 
       
     
     
       2. The method according to  claim 1 , wherein the vector V a  is one column of a Discrete Fourier Transform matrix or the vector V b  one column of the Discrete Fourier Transform matrix. 
     
     
       3. A method for measuring and feeding back channel information, the method comprising:
 sending a reference signal to a first network device; 
 receiving a codebook index sent by the first network device, wherein the codebook index corresponds to a first codebook determined in a first codebook set by the first network device, and the codebook index is determined by the first network device according to a measurement result, wherein the first codebook set comprises at least two first codebooks, a sub-vector W x  of each first codebook is formed by a zero vector and a non-zero vector, wherein the zero and non-zero vectors forming the sub-vector W x  correspond to different groups of antenna ports, wherein each first codebook comprises at least one first sub-vector 
 
       
         
           
             
               
                 [ 
                 
                   
                     
                       
                         V 
                         a 
                         0 
                       
                     
                   
                   
                     
                       0 
                     
                   
                   
                     
                       
                         V 
                         a 
                         1 
                       
                     
                   
                   
                     
                       0 
                     
                   
                 
                 ] 
               
                 
             
           
         
          or at least one second sub-vector 
       
       
         
           
             
               
                 [ 
                 
                   
                     
                       0 
                     
                   
                   
                     
                       
                         V 
                         b 
                         0 
                       
                     
                   
                   
                     
                       0 
                     
                   
                   
                     
                       
                         V 
                         b 
                         1 
                       
                     
                   
                 
                 ] 
               
               ⁢ 
               
                   
                 , 
               
             
           
         
          and wherein V a   0  and V a   1  are elements in a vector V a , and V b   0  and V b   1  are elements in a vector V  b ; and 
         determining, according to the codebook index, the first codebook determined in the first codebook set by the first network device. 
       
     
     
       4. The method according to  claim 3 , wherein the vector V a  is one column of a Discrete Fourier Transform matrix or the vector V b  is one column of the Discrete Fourier Transform matrix. 
     
     
       5. A terminal apparatus comprising:
 a receiver configured to receive a reference signal; 
 a processor configured to measure the reference signal to obtain a measurement result, wherein the processor is further configured to select a first codebook from a first codebook set according to the measurement result, wherein the first codebook set comprises at least two first codebooks, a sub-vector W x  of each first codebook is formed by a zero vector and a non-zero vector, wherein the vectors forming the sub-vector W x  correspond to different groups of antenna ports, wherein each first codebook comprises at least one first sub-vector 
 
       
         
           
             
               
                 [ 
                 
                   
                     
                       
                         V 
                         a 
                         0 
                       
                     
                   
                   
                     
                       0 
                     
                   
                   
                     
                       
                         V 
                         a 
                         1 
                       
                     
                   
                   
                     
                       0 
                     
                   
                 
                 ] 
               
                 
             
           
         
          or at least one second sub-vector 
       
       
         
           
             
               
                 [ 
                 
                   
                     
                       0 
                     
                   
                   
                     
                       
                         V 
                         b 
                         0 
                       
                     
                   
                   
                     
                       0 
                     
                   
                   
                     
                       
                         V 
                         b 
                         1 
                       
                     
                   
                 
                 ] 
               
               ⁢ 
               
                   
                 , 
               
             
           
         
          and wherein V a   0  and V a   1  are elements in a vector V a , and V b   0  and V b   1  are elements in a vector V b ; and 
         a transmitter configured to send a codebook index to a second network device, wherein the codebook index corresponds to the first codebook selected from the first codebook set. 
       
     
     
       6. The apparatus according to  claim 5 , wherein the vector V a  is one column of a Discrete Fourier Transform matrix or the vector V b  is one column of the Discrete Fourier Transform matrix. 
     
     
       7. A communications apparatus comprising:
 a transmitter configured to send a reference signal to a first network device; 
 a receiver configured to receive a codebook index sent by the first network device, wherein the codebook index corresponds to a first codebook determined in the first codebook set by the first network device, and wherein the codebook index is determined by the first network device according to a measurement result; and 
 a processor configured to determine, according to the codebook index, the first codebook in the first codebook set, wherein the first codebook set comprises at least two first codebooks, a sub-vector W x  of each first codebook is formed by a zero vector and a non-zero vector, wherein the zero and non-zero vectors forming the sub-vector W x  correspond to different groups of antenna ports, wherein each first codebook comprises at least one first sub-vector 
 
       
         
           
             
               
                 [ 
                 
                   
                     
                       
                         V 
                         a 
                         0 
                       
                     
                   
                   
                     
                       0 
                     
                   
                   
                     
                       
                         V 
                         a 
                         1 
                       
                     
                   
                   
                     
                       0 
                     
                   
                 
                 ] 
               
                 
             
           
         
          or at least one second sub-vector 
       
       
         
           
             
               
                 [ 
                 
                   
                     
                       0 
                     
                   
                   
                     
                       
                         V 
                         b 
                         0 
                       
                     
                   
                   
                     
                       0 
                     
                   
                   
                     
                       
                         V 
                         b 
                         1 
                       
                     
                   
                 
                 ] 
               
               ⁢ 
               
                   
                 , 
               
             
           
         
          and wherein V a   0  and V a   1  are elements in a vector V a , and V b   0  and V b   1  are elements in a vector V b . 
       
     
     
       8. The apparatus according to  claim 7 , wherein the vector V a  is one column of a Discrete Fourier Transform matrix or the vector V b  is one column of the Discrete Fourier Transform matrix.